A fastener driving tool using compressed air as a driving medium includes a piston provided with a driver blade striking a fastener, and a cylinder accommodating the piston such that the piston can freely reciprocate. When compressed air is supplied to a drive chamber partitioned by the cylinder and the piston, the piston is driven in a striking direction, and the fastener is struck by the driver blade. The cylinder is provided with a sleeve valve switching the state between a state of supplying compressed air to the drive chamber and a state of stopping supply of compressed air and exhausting the compressed air in the drive chamber.
The fastener driving tool includes a push lever and a trigger. When a push member provided at a tip of the fastener driving tool is pressed against a workpiece, the push lever is driven from a striking stop position, that is, an OFF position, to a striking enabling position, that is, an ON position, and the trigger is operated from a striking stop position to a striking enabling position when a worker pulls the trigger. The fastener driving tool is provided with a trigger valve in order to control actuation of the sleeve valve according to drive of the push lever and the operation of the trigger.
As described in Patent Documents 1 and 2, there are so-called continuous driving and single driving as fastener driving modes performed by a fastener driving tool including a push lever and a trigger. In addition, Patent Document 3 describes a fastener driving tool whose specification can be changed to either the specification for the continuous driving or the specification for the single driving by replacing the trigger.
A continuous driving mode is a driving mode in which a piston is driven in a striking direction when the trigger is operated from the striking stop position to the striking enabling position by a worker, the push member at the tip of the fastener driving tool is pressed against a workpiece by the worker, and the push lever is driven to the ON position, that is, the striking enabling position. When at least one of the push lever and the trigger is returned to the striking stop position, the piston comes back to a backward position. Thus, in a case where the trigger is pulled in a state in which the tip of the fastener driving tool is brought into contact with the workpiece or a switching operation between ON and OFF of the push lever is performed in a state in which the trigger is being pulled, the piston is driven in the striking direction, and fasteners can be continuously driven into the workpiece.
In contrast, the conventional single driving is a striking system in which, when the trigger is pulled after the push lever is lifted up and driven to the striking enabling position, the piston is driven in the striking direction, and a fastener is struck. In this single driving, when an ON-OFF operation of the trigger is repeated while keeping a state in which the fastener driving tool is pressed against the workpiece (state in which the push lever is turned ON), the piston reciprocates, and a fastener driving mode can be performed.